King Prithvi Narayan Shah, was enthroned at the age of 20 in Gorkha, one of 54 states in Nepal at that time.
He began expanding his realm in 1743 and after conquering Kathmandu Valley in 1768, he became monarch of modern-day Nepal, establishing a period hereditary rule that only ended in 2008 when Nepal became a republic.
One of his reasons for uniting the states was to make it harder for the region to be occupied by the British Empire.
Prithvi Narayan Shah died on January 11th 1775.
The government stopped celebrating January 11th (Poush 27) as National Unity Day, which was traditionally celebrated as a public holiday, following the political change brought by the second people’s movement in 2006.